The study, published in the Archives of General Psychiatry, found 45.8 percent of those attending college and 47.7 of those not attending college met these criteria.

The analysis of 2,188 U.S. college students between the ages of 19-25 years and 2,904 of that age not attending college found 20.4 percent of college students most frequently met the criteria for alcohol use disorders and 17.7 met those for personality disorders. Those not in college most frequently met criteria for personality disorders -- 21.6 percent -- and nicotine dependence -- 20.7 percent.

"For many, young adulthood is characterized by the pursuit of greater educational opportunities and employment prospects, development of personal relationships and, for some, parenthood," study authors Dr. Carlos Blanco of the New York State Psychiatric Institute and Columbia University in the city of New York and colleagues said in a statement.

"While all of these circumstances offer opportunities for growth, they may also result in stress that precipitates the onset or recurrence of psychiatric disorders."

They suggest "early treatment could reduce the persistence of these disorders and their associated functional impairment, loss of productivity and increased health care costs."